The husband of UFC fighter Rachael Ostovich pled no contest to assault stemming from a violent altercation in November ... and he most likely won't spend a minute behind bars.
Arnold Berdon -- who's also an MMA fighter -- was charged with 2nd-degree assault for punching Ostovich in the head, face and ribs during an argument at their Hawaii home.
Ostovich suffered a broken orbital bone in the attack -- and initially pulled out of a scheduled fight with Paige VanZant .